A linear motor is configured to convert rotary drive of a circular motor into rectilinear motion, and a transport system using the linear motor, i.e., a linear motor-based motion stage, is being widely applied in various fields such as semiconductor devices.
Such a linear motor motion stage includes a mover including an electromagnet, a magnet track in which a N pole and a S pole are alternately arranged in a line and which straightly moves the mover by generating an electromagnetic force in a gap with the mover, a base including the mover and the magnet track, and an elastic body which is connected to the magnet track and returns the magnet track which is moved by a repulsive force (i.e., reaction force) generated by movement of the mover in a direction opposite to the mover's moving direction to its original position.
In the linear motor motion stage configured as described above, when the mover moves, the base is vibrated by the reaction force and the elastic body connected to the magnet track.
Conventionally, in order to attenuate such vibration, a spring has been provided between the magnet track and the base or an eddy current attenuator has been included. However, according to the conventional method, the spring or the eddy current attenuator needs to be replaced to change a spring force generated by movement of the magnet track or characteristics of vibration attenuation occurring in the eddy current attenuator.
Further, Korean Patent No. 10-1644175 (entitled “Linear motor stage”) includes: a base; a magnet track moving on the base; a mover which is moved on a surface of the magnet track by an electromagnetic force generated in a gap with the magnet track; and a pair of first and second reaction force compensation units arranged on one side and the other side, respectively, of the magnet track and configured to attenuate a reaction force applied to the base by movement of the mover. Herein, the first reaction force compensation unit is movably provided on the base and includes a first eddy current attenuator arranged on one side of the magnet track and a first elastic member connecting the first eddy current attenuator to the base, and the second reaction force compensation unit is movably provided on the base and includes a second eddy current attenuator arranged on the other side of the magnet track and a second elastic member connecting the second eddy current attenuator to the base.